In many fields there is a need to join tubes together at right angles to their longitudinal axes--such joints are known as saddle joints and, by way of example, one is shown schematically in FIG. 1. In order to join a first tube end on to the side of a second tube in this way it is necessary to cut the end of the first tube so that it matches the exterior shape of the second tube allowing it to be joined to the second tube in end-to-edge abutment. In even the simplest cylindrical case, involving circular-cylindrical tubes, where a first tube joins a second tube at a right angle it is a relatively complex operation to determine exactly the shape that the end of the first tube needs to be cut to in order to fit the second tube.
The conventional method for reproducing the necessary shape of the end of the first pipe in order for it to fit to the second pipe involves the use of relatively complex Euclidean geometry calculations to arrive at a curve which can be drawn on a piece of paper. The paper is wrapped around the tube and used as a guide-line along which a cut is made.
A skilled and experienced technician is generally required to carry out these calculations and the process is a protracted one.
Furthermore, in such a lengthy and complex process there is always a significant risk that an error may be made, which can result in an expensive mistake.
Evidently there is a need for a simpler method of reproducing the shape to which a first tube must be cut when joining it in end-to-edge abutment to a second tube.